Telephone-exchange system.



E. E. HINRI'CHSEN. TELEPHONE EXCHANGE SYSTEM.

APPLICATION FILED JUNE 8, I915.

l Patented Aug. 7,1917.

To all whom it may concern:

EDWARD E.'HINRICHSEN, OF NEW YORK, N. Y1, ASSIGNOR, BY MESNE ASSIGNMENTS, TO WESTERN ELECTRIC COMPANY, INCORPORATED, A CORPORATION OF NEW YORK.

TELEPHONE-EXCHANGE SYSTEM.

Be it known that I, EDWARD E. HINRICH- sEN,'a citizen of the United States, residing at New York, in the county of New York and State of New York, haveinventedcertain new and useful Improvements in Telephone-Exchange Systems, of whichthe following is a full, clear, concise, and exact description. V

This invention relates to telephone exchange systems, and more particularly to telephone systems of the class in which the subscribers line is available for toll connections at all times. 1

It i the object ofthis invention toprovide means whereby toll calls may be given precedence overall other calls, even when a subscribers line wanted for a long distancecall happens to be in use on alocal connection.

In accordance with this invention means" are provided whereby an answering or A operator is given a peremptory disconnect signal in the event the called subscriber for a toll connection is already engaged in conversation. This means comprises an auxil iary or special connecting circuit located at a switching operators position, said circuit l including means which effect the operation of a signaling device, such as the flashing of a line supervisory lamp, 'forming'a part of the A operators cord circuit associated with said subscribers line. When the A j operator observes the flashing ofthe subscribers supervisory lamp, itwill be a signal for her to take down the connection then existing with the wanted subscribers line, thus rendering said line available for toll I purposes.

I The accompanylng diagrammatically one embodiment QfthlS,

Special'features of the switching operators connecting circuit contemplatedby this invention will be apparent upon a reading of the specification.

drawing illustrates invention. 7

A subscribers substation is connected by means of line wires 2, 3yto multiple acks 4 at a central oiiice. Associated with-theline circuit is the usual line relay '5, which controls a line lamp 6 and a cut-off relay 7 A portion of an A operators cord circuit is shown which includes only the equipment necessary to illustrate. th s nvention, Sl/1(1 equipment comprising an answering plug 8 having the tip and ring strands thereof con nected' to repeating coil windings in the "usual manner, Included in the'ring strand is aisupervisory relay 9 which controls the circuitof a supervisory lamp10. Likewise only the portion necessary to illustrate this invention is shown of a B or switching operators cordcircuit. "The auxiliary orspecial connecting circuit which is the feature of this invention terminates at one of its ends in a'fjack l l and at the other in a plug 16.

This circuit is preferably located at the switchsboard of the B or switching operator.

Inidescribing theoperation of the apparatus'illustrated in the drawing, we will assume that the substatio'nl' is connected to another substation bytheA operators cord circuit, and that a toll operator has received a callv for-substation 1'. The switching orB operatorh'aving' made the usual busy testto determine whether the substation: 1 is in use and findingiit busy-,linserts the calling plug 13-of. a switching trunk circuit into the jack 14 of the auxiliary circuit. Having .done this she next operates a listening key 73' and inserts the calling plug 16 of this'circuit into one of the multiple jacks, 4:; By these acts on the partof the operator several circuits are established, o1 e of which is a circuit for effecting the operation of the relay 15, which may be tracedas follows: battery 17, transformer 18, resistance-19, conductor 20, lower winding of the relay 15, conductor 21, winding .of relay. 22, conductor 23, contact24, conductor 25, sleeveside oftheplug 16 and jack 4. respectively, conductor 26, coil of relay 7, vto-ground. The circuit just described energizes the relay 22, which in pulling. up its armature closes contact 31, thus completing'a circuit through the windings of relay 15, which may be traced as follows: battery 17, transformer 18, resistance 19, conductor' 20, upper and lower windings of relay 15,.conductor 32, contact 31, to ground. It may be mentioned here that the relay 15 is differentially wound, and the upper winding isso proportioned to the lower winding that-in certain instances when both windings are energized the upper one neutralizes into a multiple jack of a line not in use. At other times, as for example, when a plug of a cord or trunk circuit is inserted into another of the multiple jacks, either before or after the insertion of the plug 16, the currents through the windings of the relay 15 are so changed by changing the resistance of the circuit including said relay, that it operates. Controlling the operation of a differentially wound relay by varying the amount of resistance in its energizing circuit, by either shunting a part thereof or adding more, is an old expedient and well understood in the art.

The operation of the relay 15 closes a cir- :cuit through the lower winding of the relay 33 which may be traced as follows: battery 34, lower winding :of relay 33, conductor 35, contact 36 of relay 15, to ground. The men gization of the relay 33 opens contact 37 and closes contact 38, but the closure of this contact has no effect at this time as the con tact 49 is open. The B operator may now converse with the subscriber at substation 1, and having, informed said subscriber that he is wanted on a toll connection the operator restores the listening key 73. Upon the restoration of the listening key 73, the upper winding of the relay 33 is bridged across the tip and ring strand of the A operators cord circuit which maintains the supervisory re.- lay 9 energized over a circuit which may be described as follows: battery 11, winding of supervisory relay 9, ringside of the plug 8 and jack 4, over line wire 3 to the multiple jack in which the plug 16 has been inserted, through the ring side of the plug 16, contact 39, conductor 40, contact 41, conductor 42, upper winding of the relay 33, conductor 43, contact 44, conductor 45, contact 46, tip side of the plug 16 and jack 4, line wire 2, back to the tip side of the answering jack 4 and plug 8, to ground. The bridging of the upper winding of the relay 33 in this circuit prevents the lighting of the supervisory lamp 10 by maintaining the relay 9 in an energized condition.

Simultaneously with the completion of the above traced circuit by the restoration of the listening key 73, the following circuit is established through the relay 50: battery 34, contact 38, conductor 47, contact 49, conductor 48, coil of relay 50, to ground. The consequent operation of relay 50 establishes 1 the following circuit through an interrupting device 51 which circuit may be described as follows: battery 52, interrupter 51, conductor 53, contact 54, conductor 25, sleeve side of the plug 16 and jack 4, through the sleeve side of multiple jack 4 containing plug 3, lamp 10, to battery 12. It will be noticed that the battery 52 is of opposite polarity to that of battery 12, and this difference in polarity increases the strength of the current flowing over the above circuit 50 that the lamp 10, normally extinguished, will be intermittently flashed by the interrupting device 51. The flashing of this lamp may be taken as a peremptory signal for the A operator to withdraw her answering plug 8. a

A busy tone is placed upon the ring strand of the jack 14 by the closure of contact 56 for the purpose of notifying the toll opera tor that the switching operator is attempting to make connection with the desired party. The circuit of this tone may be traced as follows: battery 57, coil or relay 58 (which would ordinarily be a supervi- :sory relay), ring side of the plug 13 and jack 14, contact 56, conductor 59, resistance 70, transformer 71, interrupter 72, to ground.

The A operator having observed the flashof the supervisory lamp 510, withdraws the answering plug 3. The withdrawal of this plug produces the denergization of the relays 33 and 50. It may be stated here that a resistance is inserted in a shunt around the interrupting device 51-, so that the cutoff relay will be maintained energized during the interval required for the relays 33 and 50 to restore to normal position upon the removal of the plug 8. This feature prevents the inadvertent flashing of the line lamp 6. The rdenergization of the relay 33 closes a circuit through the relay 60 which may be traced as follows: battery 34, contact 37, conductor 61, coil of relay 60, conductor 62, contact 63, conductors 64, 32, contact 31, to ground. The actuation of the relay 60 connects the subscribers line through to the switching trunk of the switching operator by closing its front contacts and 66. Circuit connections are now made from the toll operators position through to the substation 1.

A busy tone is placed upon the sleeve of the multiple jack 4 associated with the subscribers line for indicating the busy condition of thi'sline to a second operator. The circuit of this busy tone may be traced as follows: battery 17, transformer 18, resist ance 19, conductor 20, lower winding of relay 15, conductor 21, winding of relay 22, conductor 23, contact 24, conductor 25, sleeve side of plug 16 and jack 4- respectively, conductor 26, coil of relay 7, to ground. To provide against the possibility of the switching operator in advertently leaving the plug 16 in the multiple ack 4 when the subscriber at substation 1 has replaced his receiver upon the switchhook, the supervisory lamp 67 is provided. The circuit for this lamp is established over the following path: battery 17, transformer 18, resistance 68, lamp 67, contact 69, conductors 64, 32, contact 31, to ground. The switching operator observing the lamp 67 lighted, will know that she has failed to disconnect the lug 16 of .the auxi iary circuit from the line of Substation 1.

connect with the line, inform the wanted party that heis wanted on long distance and then give the A operator a peremptory disconnect signal to take down the then existing connection with the wanted. subscriber. This feature is important in that it gives precedence under all circumstances to long distance calls; prevents the inconvenience of reestablishing toll connections up to the point of the wanted subscriber, and quite often will save a toll call which would otherwise be lost in case the wanted subscribers line is not available when the connection was first set up.

What is claimed is:

1. In a telephone system, a subscribers line terminating in multiple line aks at a central oiflce, a link circuit and a switching operators connecting circuit each adapted to be connected with said line, a source of current and a line supervisory lam connected therewith and included in said link circuit, a manually actuated switch associated with said connecting circuit, means associated with said connecting circuit and controlled by said switch whereby the operator may notify a subscriber on a busy line regarding a waiting call, and automatic means associated with said connecting circuit and controlled by said switch for'flashing said supervisory lamp when said link circuit and said connecting circuit are simultaneously connected with said line.

2. In a telephone system, a subscribers line terminating in multiple line jacks at a central oflice, a link circuit and a switching operators connecting circuit each adapted to be connected with said line, a source of current and a line supervisory lamp connected therewith included in said link circuit, manually and automatically operable switching means included in said connecting circuit, and means for causing said supervisory lamp to be flashed when said circuits are simultaneously connected with said line, said means being under the conjoint control of said switching means. a

3. In a telephone system, a subscribers line terminating in multiple line jacks at a central oflice, a link circuit and a switching operators connecting circuit each adapted to be connectedwith said line, a source of current and a line supervisory lamp connected therewith included in said link circuit, manually and automatically operable switching means included in said connecting circuit, said manual switching means controlling the operation of said automatic switching means, and means associated-with said connecting circuit for causing said supervisory lamp to be flashed when said link circuit and said connecting circuit are simultaneously connected with said line, said means being underthe conjoint control of said switching means.

I 4:. In a telephone system, a subscribers line'terminating in multiple line jacks at a central office, a link circuit adapted to be connected with said line, a source of current and a line supervisory lamp connected therewith included in said link circuit, a switching operators connecting circuit terminating in a plug at one end thereof, a circuit interrupting device, switching means for ineluding said interrupting device in a circuit 7 with said supervisory lamp, and asource of current of opposite polarity to that normally associated with said lamp, said source of current being adapted to be interrupted by said interrupting device, whereby said lamp is caused'to be flashed when said link circuit and said connecting circuit are simultaneously connected with said line.

5. In a telephone system, a plurality of subscribers lines terminating in multiple line jacks at a central office, a link circuit for connecting any pair of said lines together, a switching operators connecting circuit adapted to be included in a toll connection,

means included in said connecting circuit for permlttmg a switch ng operator to make connection with a busy line, a manually ac tuated listening key in said connecting circuit, and means associated with said connecting circuit and controlled by said listening key for giving a busy tone to a toll op erator when said connecting circuit is connected with a busy line whereby the toll operator is informed that the switching operator is endeavoring to establish a toll connection with said busy line.

6. In a telephone system, a subscribers line terminating in multiple jacks at a central oflice, a link circuit adapted to be connected with said line, a signaling device included in said link circuit, a plug associated with said signaling device, a switchin operators connecting circuit adapted to e included in a toll connection, means included in said connecting circuit for permitting a switching operator to make connection with said line when said plug of said link circuit is inserted in one of said jacks, means for giving peremptory disconnect signal through the operation of said signaling device, and means for automatically establishing a circuit over the talking conductors of said switching circuit upon the removal of said plug from said line.

7.'In a telephone system, a subscribers tral ofiice, a link circuit adapted to be connected with said line, a source of current and a line supervisory lamp c0nnectedthere- With included in said link circuit a switching operators connecting circuit terminating in a plug at one end thereof, means associated with said connecting circuit for causing said supervisory lamp to be flashed when the plug of said connecting circuit is inserted in the multiple jack of a busy line, and means independent'of said plug under the control of the switching operator for controlling said flashing means.

In Witness whereof, I hereunto subscribe my name this 5th day of June, A. D. 1915. 15

EDWARD E. HINRIOHSEN.

Copies of this patent may be obtained for five cents each, by addressing the Commissioner of Patents,

' Washington, D. (1. 

